A battery system in an eco-vehicle has been developed to have increased energy density and output density in response to increased demand for high output/high energization, but battery stability has been degraded. Therefore, in order to improve the stability of the battery system, research continues to be performed regarding vehicle cooperative control, battery management system (BMS) active protection, pack passive protection, and cell robustness design.
According to the related art, a method has been suggested where a battery charge is blocked by breaking a lead tap when a cell swelling occurs at the time of overcharge of the battery, or a swelling of an end plate is used.
In particular, as illustrated in FIG. 1, an apparatus for physically preventing overcharge turns off a relay Ry of 12V when a switch SW disposed in the front of a cell is pressed at the time of the overcharge, to thereby block a power relay assembly (PRA). According to the apparatus for physically preventing overcharge described above, since the lead tap of the cell becomes thick as the cell becomes high capacity, the breaking of the lead tap is not smooth, or it is impossible to reuse such as an additional charge after a physical fail situation.
In addition, as illustrated in FIG. 2, the apparatus for physically preventing overcharge has a structure in which the cell expands due to the overcharge of the battery B, and the cell presses the switch SW disposed at the outermost of the cell to operate the switch SW. However, since a degree of expansion of the cell is about several millimeters (mm), it is difficult to determine an appropriate operation time point of the switch and there is the possibility of malfunction of the switch due to transport and impact.
As such, the apparatus for physically preventing overcharge prevents the battery from being used any more by performing detection and protection functions after an overcharge event.
However, such an apparatus for physically preventing overcharge has a limit in that a protection operation is performed after a fail situation in which the cell is swelled together with an increase in temperature at the time of the overcharge of the battery.
In addition, the apparatus for physically preventing overcharge may not perform the cooperative control and the active protection in a state in which the BMS is structurally inoperable.